The present disclosure relates to a fixing device and an image forming apparatus.
An electrophotographic image forming apparatus includes a fixing device that fixes toner on a recording medium. The fixing device for example fixes toner by applying heat and pressure onto the recording medium while the recording medium carrying unfixed toner is passing through a fixing nip formed between a pressure roller and an endless rotatory heating belt. For example, a heater that heats the fixing nip is provided inside of the rotatory heating belt.
The rotatory heating belt is prone to deformation if heated by the heater while in a suspended state. In case of abnormal rotation of the rotatory heating belt, therefore, it is necessary to stop the heating by the heater as early as possible.
For example, a certain fixing device can determine the state of rotation of a rotatory heating belt (a first rotatory body) through periodic detection of a position of the outer circumferential surface of the first rotatory body in terms of a radial direction using a sensor.